Jacksonville Jaguars at Indianapolis Colts

The Jaguars have won four of the last five matchups against the Colts, outscoring them 158-77. However, three of those wins came with Andrew Luck not playing. Luck is 6-2 in his career against Jacksonville with five of the wins by 17-plus points and the two losses by a total of eight points.

The Jaguars have lost four in a row, getting outscored by 68 points. That's the worst differential the team has suffered in a four-game span since Weeks 2-5 of 2014 (-85) - a stretch which saw Blake Bortles take over as QB in Week 3.

The Colts opened 1-5 but have since won two straight games, rushing for more than 200 yards in both. The last time the Colts had rushed for 200-plus yards in back-to-back games within a season was 1985. They've never done it in three straight games.

The Colts have 23 touchdown passes this season, tied with the Buccaneers for second-most in the league (Kansas City -- 29). On the other side of the ball, the Jaguars' defense has allowed only nine passing touchdowns this season, tied with the Cardinals for the fewest in the NFL.

Leonard Fournette is set to return for the Jaguars. Since the start of his career, the Jaguars have rushed 47.3 percent of the time when he has played and 38.9 percent of the time when he has been out of the lineup. That has translated to 28.7 more rushing yards per game (136.7 to 108.0) in the games with him.

Luck has thrown for at least three touchdown passes in five consecutive games, something he had never previously done in more than three straight games. He has not been sacked in three straight games, also the longest streak of his career.

At the highest point of their quarterback careers, the Indianapolis Colts' Andrew Luck and Jacksonville Jaguars' Blake Bortles advanced their respective teams to AFC Championship Game losses at New England.

But aside from both being first-round draft picks who are bringing 3-5 teams coming off a bye into an AFC South Division game Sunday at Lucas Oil Stadium, that's about where the similarities end.

Luck, after missing 2017 due to shoulder surgery, is having a career year and the Colts are coming off back-to-back wins for the first time since 2016. He's on pace for career bests in most major passing categories, proof that he's better than when he led the team to a 41-7 loss to the Patriots just one step away from the Super Bowl in the 2014 postseason.

Bortles, who had one of his best games in a 24-20 AFC title game loss to the Patriots in January, is at the helm of a sputtering offense that is 30th in points scored and largely to blame for a four-game losing streak. The Jaguars have been outscored 114-46 during that span.

Neither team can afford a loss, considering division leader Houston (6-3) is on a six-game winning streak, so this game takes on added importance. Not that at least one Colts player wants to look at it that way.

"Not make or break," said Colts four-time Pro Bowl wide receiver T.Y. Hilton. "We know what we need to do and how to get there. We've just got to win."

Indianapolis could find itself right back in the hunt of the AFC South title despite winning just once in their first six games. The Colts have won back-to-back games and play their next three games in the confines of Lucas Oil Stadium.

Bortles knows the margin for error is very small for the Jaguars the rest of the season.

"I think they are all must-wins for me from here on out," Bortles said. "I think we have to win them all. Maybe you get lucky and lose a couple and find a way to still make it, but I think you have to win them all and for sure starting with the first one."

Bortles, whose 81.4 passer rating ranks 31st among quarterbacks who have started multiple games, is also dealing with a left, non-throwing shoulder injury. He says he'll be OK, but he's faced continual scrutiny for an offense that has averaged just 10.5 points in its five losses. He has just 10 touchdown passes with eight interceptions, has lost three of five fumbles and taken 18 sacks.

Luck, whose 96.2 passer rating ranks 15th, is directing an offense that has scored 30 or more points in three consecutive games, the first time that's happened for the franchise since 2010. And his 23 TD passes are the most in his career for the first eight games and second most in team history, trailing only Peyton Manning's 26 in 2004.

Whereas Bortles will be facing an inconsistent Colts defense that, among other negatives, is 25th in points allowed at 26.6 per game, Luck is facing the NFL's No. 1 pass defense. The Jaguars allow just 190 passing yards per game. And they're also second in fewest total yards allowed at 313.2 per game.

"They have really good players all over," Luck said Wednesday of the Jaguars. "They've got guys who can cover, they've got really, really good linebackers, they've got a really stout, strong defensive line and they play the system really well. So it's a combination of a lot of factors. At the end of the day, this game is about the players on the field and they have a lot of good ones."

Jaguars head coach Doug Marrone has been particularly impressed with how the Colts have protected Luck. A reshuffled offensive line that has used 11 different starters has kept Luck from being sacked on 156 consecutive pass attempts. Couple that with a resurgent rushing game that has amassed more than 200 yards in the last two wins and it's no secret why the Colts offense has been clicking at a high level.

"It's a really, really good group and honestly right now collectively, I would have to say when you look at them on film they're probably the best offensive line that we have seen this year," Marrone said.

Bortles, the third overall pick in 2014, concedes his offense needs to vastly improve come Sunday.

"If I knew, if anybody knew," Bortles said of the issues, "we'd fix it in a heartbeat."

Colts first-year head coach Frank Reich is confident his fixed offensive line will be able to block a strong Jaguars defensive front, but admits the opponent poses the "toughest test" for his offense this season.

"It is having really good cover guys," Reich said, "but really I think it starts up front with the pressure that they get on the quarterback. That combination is obviously a really good combination to have. The good secondary play they are getting -- sometimes you get good secondary play just because you get good pressure and you could have average corners and good pressure and it looks good in the back end. This team is good up front, but they are also good on the back end as well."

The Colts must contend with a 4-3 scheme that relies on a front four led by pass-rushing ends Calais Campbell and Yannick Ngakoue, who each have a team-high five sacks. Because the Jaguars can count on standout cornerbacks Jalen Ramsey and A.J. Bouye in man-to-man coverage, that frees up linebackers to blitz and speed up the internal clock of opposing passers.

The Jaguars appear to have good news on the horizon. Running back Leonard Fournette practiced for the second time this week and while still showing up on the injury report, all indications are that he'll be in the starting lineup come Sunday. That's a plus. The Jaguars are 2-0 in the two games he's played in this season. Without him, they are 1-5.

If Fournette is in the starting lineup on Sunday, the Jaguars will not hold back on using him. Marrone made that crystal clear on Sunday, when he was asked if the Jaguars would limit his carries to any degree.

"You're asking me if he is able to play, are we going to kind of hold back or just kind of work him into it? We are full-boring everybody," Marrone said. "Once a guy is ready to play, that has to be our expectation."

"Another guy we got to fight, defend and stop," Colts defensive tackle Al Woods said of Fournette. "So it's going to be interesting, it's going to be a dog fight. Can't wait."